In a vehicle such as an automobile, generally, a seat belt device which restrains an occupant is provided in a seat including a seating part on which the occupant sits and a backrest pan positioned on the back surface side of the occupant. Such a seat belt device includes a webbing which restrains the occupant, a retractor which performs winding of the webbing, a guide anchor which is provided in a vehicle body and guides the webbing, a belt anchor which fixes the webbing in the vehicle body, a buckle which is disposed on the side surface of the seat, and a tongue which is disposed in the webbing. When the tongue is fitted into the buckle, the occupant is restrained in the seat by the webbing.
In the retractor, a pretensioner which removes the looseness of the webbing during an emergency such as a collision of the vehicle is disposed in many cases. In addition, recently, it is considered that a resin column-shaped rack (resin rod) is used as a moving member (power transmission member) which rotates a spool at the time of the emergency (for example, see JP-A-2014-201156).